Plasma MMP and TIMP quantification methods Blood samples will be taken from peripheral veins by nursing staff.MMP and TIMP levels will then be measured using commercially available sandwich enzyme-linked immunosorbent assay (ELISA) kits which have previously been validated for use in human tissue homogenates.Serum MMP levels will be determined using MMP-2 and MMP-9 monoclonal antibodies.Levels of TIMP-1 and -2 will be determined using monoclonal antibodies.